Method for plant growth regulation

ABSTRACT

A METHOD FOR REGULATING THE GROWTH OF PLANTS BY APPLYING TO GROWING PLANTS AN EFFECTIVE AMOUNT OF ALKLYLSULFONYL-, HALOALKYYLSULFONYL, ARALKYLSULFONYL OR ARYLSULFONYLHYDRAZONES OF 2,6-DIHALOBENZALDEHYDES IS DESCRIBED.

United States Patent Oflice 3,817,740. Patented June 18, 1974 ABSTRACTOF THE DISCLOSURE A method for regulating the growth of plants byapplying to growing plants an effective amount of alkylsulfony1-,haloalkylsulfonyl-, aralkylsulfonyl or arylsulfonylhydrazones of2,6-dihalobenzaldehydes is described.

BACKGROUND OF THE INVENTION This application is a continuation-in-partof our prior copending application Ser. No. 90,074, filed Nov. 16, 1970,now U.S. Pat. 3,709,936.

This invention relates to a method for regulating the growth of higherplants by applying to them compounds which are substituted hydrazones of2,6-dihalobenzaldehydes, and more specifically hydrazones substituted byalkylsulfonyl, haloalkylsulfonyl, aralkylsulfonyl or arylsulfonylradicals. The method of the invention includes use of the specifiedplant growth regulator compounds with various suitable diluents oradjuvants, both inert and active.

Methods for regulating plant growth, including complete inhibitionthereof owing to general or specific phytotoxicity, are described in anumber of patents, including US. Pats. 3,234,255; 3,344,153; 3,326,663;3,165,549; 3,383,195 and 3,491,145, and French Pat. 1,532,014 andothers.

Plant growth regulating utility of practical value is relativelyuncommon, although widely sought. In some cases chemical compounds maybe plant growth regulators at particular concentrations and may be veryphytotoxic, that is herbicidal, at higher concentrations. An example ofthis is 2,4-dichlorophenoxyacetic acid. In fact, the term plant growthregulator, as sometimes used, includes herbicidal properties, althoughit is not used herein in that sense. Plant growth regulators maystimulate or retard growth of the plant or may affect the growth of oneparticular part of the plant without affecting other parts of the plant.In some cases, plant growth regulators may be found which direct theenergy of the plant to a particular aspect of its development which ismost desirable, that is they may increase the yield of the edibleportion of the plant. This may occur by a variety of mechanisms, forexample increased flowering, increased bud set, enlargement of theedible portion and the like. Such eifects are particularly advantageous.

The methods for application of agricultural chemicals in general, andplant growth regulators in particular, utilize the distribution of arelatively small amount of diluted material over a large area. Examplesof regulators so used are maleic hydrazide and gibberellic acid.Accidental localization of the effective ingredient can occur, however,resulting in phytotoxicity if the ingredient is herbicidal at higherconcentrations. For this reason plant growth re,-

ulators with very low phytotoxicity are desirable. Certain knownherbicidal compounds are derived from 2,6-dichlorobenzaldehyde, e.g.2,6-dichlorobenzaldehyde oxime, 2,6 dichlorobenzaldehyde semicarbazone,N,N-dimethyl- 2,6-dichlorobenzaldehydrazone and2,6-dichlorobenzonitrile, a commercial herbicide. However, it has not,so far as applicants are aware, been observed by others heretofore thatsulfonylhydrazone derivations of 2,6-dihalobenzaldehydes are activeherbicides. It is believed to be highly surprising and unexpected thatthe compounds used in the method of the present invention are useful andnontoxic to plants at dosages which produce valuable plant growthregulating effects.

SUMMARY OF THE INVENTION The invention relates to a hithertounknownmethod of use of compounds of the formula X Formula. I

wherein X is a halogen and R is alkyl or haloalkyl of one to 16 carbonatoms, benzyl, phenyl or substituted phenyl as plant growth regulators.

The compounds which are useful in the method of the invention are thosewherein X is halogen, i.e. fluorine, chlorine, bromine or iodine. Both Xsubstituents may be the same halogen, or they may be difierent. The mostreadily available and synthetically accessible species of the abovegeneric formula are the 2,6-dichloro compounds, and generally thecompounds symmetrical with respect to the X substituents are the morereadily available. It is preferred that X be chlorine or bromine, andpreferably that one X substituent always be chlorine in the com poundsused in the method of the present invention. Nonsymmetrical variationsof 2,6-dihalobenzaldehydes are known, and methods for using compounds ofFormula I derived from such variations are a part of the presentinvention.

Compounds used herein wherein R is straight or branched chain alkyl orhaloalkyl of one to about 16 carbon atoms have been found to be activeas plant growth regulators. Compounds containing up to about six carbonatoms, i.e. lower alkyl or haloalkyl are presently preferred.

Compounds used herein wherein R contains a phenyl ring, i.e. benzyl,substituted benzyl, phenyl or substituted phenyl are active as plantgrowth regulators. The phenyl ring may be substituted by one to fivesubstituents. However, compounds containing one to three substituentsare more readily accessible synthetically, and are presently preferred.These substituents may be the same or different. Substituents which maybe present include halogen, lower alkoxy, lower alkyl, lower haloalkyland lower alkanoylamido. It is presently preferred that when thesubstituents are alkoxy, alkyl, haloalkyl or alkanoylamido, they containone or two carbon atoms.

The compounds useful in the method of the invention are prepared by thereaction of a 2,6-dihalobenzaldehyde with an alkylsulfonyl,haloalkylsulfonyl, aralkylsulfonyl or arylsulfonyl hydrazide. Some2,6-dihalobenzaldehydes are readily available, and some others arereported in the chemical literature. See, for example, G. Lock,Berichte, Vol. 68, page 1505 (1935); J. F. Bunnett et al., J.A.C.S.,Vol. 83, page 2512 (1961); and British Pat 1,080,167, is-

3 sued Aug. 23, 1967. All of the 2,6-dihalobenzaldehydes are availablethrough the use of the synthetic techniques reported for the preparationof such compounds.

Some of the alkyl and aryl sulfonylhydrazides are known in the art, andall of the substituted hydrazides used to prepare the compounds employedin the method of the present invention can be synthesized by knownmethods, such as reaction of the correspondingly substituted sulfonylhaldies with hydrazine. The haloalkylsulfonyl hydrazides disclosedherein as reactants are not reported in the literature, and theirsynthesis is described hereinafter.

The following reaction scheme describes the preparation of the compoundsuseful in the method of the inven-- tion:

x @030 Nnmnsoza x I 011=NNHS02R The hydrazide is first reacted with thebenzaldehyde. The mixture is then dissolved in refluxing ethanol, andthe reaction is heated at reflux temperature (approximately 80 C.) forone to several hours to insure the completion of the reaction. Theproduct generally is obtained as a solid precipitate upon cooling of thereaction mixture.

The method for plant growth regulating activity using the compounds ofFormula I was demonstrated by employing them in greenhouse and field onseveral plant species.

In the greenhouse tests, the plants were sprayed to run-off with asolution of the compounds of the invention in acetone with a surfactantsuch as Tronic (a mixture of alkyl aryl oxyethylene glycols mixedpetroleum distillates, alkyl sulfates and alkyl amine acetates). Theconcentration of the chemical is 500 to 2,000 parts per million (weightper unit volume), and the surfactant concentration is 0.25 to 1.0percent. The plants were checked daily for any effect on or alterationof the development of the plant compared to untreated controls. Thecompounds of the invention were found to be active in producing plantgrowth regualtory effects. In particular, bean plants (Phaseolusvulgaris var. pinto) were found to undergo dwarfing of the plant withincreased bud and bean production. Dark green coloration of the treatedplants were noted. Such regulation was noted after two to three weeks.Such an effect is extremely desirable, suggesting that more plants couldbe planted in a given area while each plant produces more beans.

When a field test was conducted and growing soybeans were treated with asolution of 500 parts per million of active compound, a significantweight increase in the crop of beans was observed as compared with thecrop from an untreated control group of soybean plants.

Compounds of Formula I are also useful in promoting the rooting ofcuttings of ornamental and food-producing plants.

Among the most active of the compounds were the following:

2,6-dichlorobenzaldehyde 4-bromobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde benzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 4-methylbenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 4-nitrobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 4-methoxybenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 4-fiuorobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 2,4,S-trichlorobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 3-nitrobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 2nitrobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 3,4-dichlorobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 2,5-dichlorobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 4-chloro-3-nitrobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde 2,3,4-trichlorobenzenesulfonylhydrazone,

2,6-dichlorobenzaldehyde methanesulfonylhydrazone,

2,6-dichlorobenzaldehyde ethanesulfonylhydrazone,

2,6-dichlorobenzaldehyde butanesulfonylhydrazone,

2,6-dichlorobenzaldehyde fluoromethanesulfonylhydrazone,

2,6-dichlorobenzaldehyde chloromethanesulfonylhydrazone and2,6-dichlorobenzaldehyde phenylmethanesulfonylhydrazone.

In order to modify the growth of plants, the compounds of Formula I canbe used alone as plant growth regulators, for example as dusts orgranules of the compounds, or preferably they may be applied informulations containing the active ingredients in a horticulturallyacceptable extending medium. The formulations are comprised of one ormore active ingredients and one or more adjuvants and/or carriers.Specific formulations are useful to facilitate the application of thecompounds and to and to achieve specific biological objectives such ascontrolling the availability of the compound, improving adherence toplants, and the like, as it is well known to those skilled in the art.

The compounds of Formula I may be formulated as wettable powders,emulsifiers concentrates, aqueous or non-aqueous solutions and/orsuspensions, granules, dusts and the like. Said compounds as such can befinely divided and dispersed or suspended in any of the usual aqueousmedia. Spreading agents, wetting agents, sticking agents or otheradjuvants can be added as desired.

When emulsifiable concentrates are prepared, the active ingredient canbe present in concentration of about 5 percent to 60 percent or more,depending upon its solubility. The units of concentration are weight perunit weight. The active ingredients are soluble in common organichorticultural solvents such as benzene, toluene, xylene,dichloromethane, chloroform, hexane and heptane or less highly refinedaromatic or aliphatic hydrocarbons and mixtures thereof. Examples ofthese are coal tar fractions, straight run petroleum distillates,thermolytically or catalytically cracked hydrocarbon oil, gas oil, lightlubricating oil fractions, kerosenes, mineral seal oil, and the like. Inappropriate cases, oxygenated solvents such as ketones may be used in oras the carriers. These concentrations can be dispersed in water topermit the use of an aqueous spray. A mixture with a small amount of anorganic surface active agent capable of lowering the surface tension ofwater is preferred, so as to produce more or less stable emulsions.

Examples of surface active agents variously known as dispersing agents,wetting agents or emulsifying agents comprise soft or hard soaps,morpholine or dimethylamine oleate, sulfonated fish, castor andpetroleum oils, sodium salts of lignin sulfonic acid, alkylated aromaticsodium sulfonates such as decylbenzene sodium sulfonate, dodecylbenzenesodium sulfonate, butyl or other amine salts of decyl or dodecylbenzenesulfonic acid, sodium lauryl sulfate, disodium monolauryl phosphate,ethylene oxide condensation products of alkyl phenols, as for exampleoctyl phenol, ethylene oxide condensation products of tall oil andethylene oxide condensation products of higher alcohols or highermercaptans. Mixtures of two or more surface active agents are alsofeasible. Generally, the surface active agent will comprise only a smallproportion of the composition, say 0.1 to 15 percent by weight of thetoxicant.

The formulation of dry compositions for application as granules, dustsor for further dilution with liquid carriers is readily accomplished bymixing the active ingredient with a solid carrier. Such solid carrierswill be of various sizes from dust to granules. The techniques for suchformulations are well known to the art. Suitable carriers includecharcoal, talc, clay, pyrophyllite, silicas, fullers earth, lime,diatomaceous earth, flours, such as walnut shell, wheat, soya bean,cottonseed and wood flours, magnesium and calcium carbonate, calciumphosphate and the like. Powders may be granulated by the use of suitablebinders such as cellulose derivatives, for example ethyl orcarboxymethyl, corn syrup and the like.

When wettable powders are prepared the active ingredients can be presentin concentration of about to 75 percent but preferably about 50 percent.The presently preferred carrier is clay, and it is preferred to add acombination of surface active agents such as a sodium alkyl naphthalenesulfonate and a sodium lignosulfonate in an amount about one percent byweight of each ingredient.

The method of the invention is carried out, using compounds of thegeneral Formula I, in compositions adapted for application to the plantsto be treated, as those formulations are described herein. Theformulations are diluted with water if necessary and are applied byspraying, spreading, dusting or the like. The rate of application willof course vary, but the more active compounds of Formula 1 exhibitinteresting plant growth regulating effects on bean species such assoybeans and pinto beans at the application rate of about 500 to 1,000parts per million (weight per unit volume). It is of course to beexpected that local conditions, for example temperature, humidity,moisture content of the soil, nature of the soil, stage of growth of theplant and the like, may require greater or smaller amounts. Effectiveresolution of these factors is within the skill of those versed in theart. Likewise it is apparent that not all of the compounds includedwithin the scope of the invention have equal activity.

The plant growth regulating compositions as used in the method of theinvention may contain one or more of the compounds set out hereinbeforeas the sole active species, or they may contain in addition theretoother biologically active substances. Thus, insecticides and fungicidesmay be incorporated in the compositions. Further, if desired, thecompositions may contain fertilizers, trace metals or the like, and whenapplied directly to the soil may additionally contain nematicides, soilconditioners, other plant growth regulators and/or herbicides of similaror different properties.

The preparation and properties of compounds of Formula I useful in themethod of the present invention are more specifically illustrated by thefollowing examples.

Example 1 To a stirred mixture of 7.3 gm. of4-bromobenzenesulfonylhydrazide (0.029 mole) in 50 ml. of water is addeda solution of 5 gm. of 2,6-dichlorobenzaldehyde (0.0286 mole) in 50 ml.of ethanol in one batch. A solid precipitates, and 500 ml. of ethanol isadded. The mixture is heated to reflux and maintained at refluxtemperature for one hour. The solution is then filtered hot and allowedto cool slowly. The precipitate is collected by filtration and washedthree times with 75 ml. of water. The white solid is2,6-dichlorobenzaldehyde 4-bromobenzenesulfonylhydrazone, M.P. 181-183C. The method of the invention is carried out by applying the compoundat concentration of 5001,000 ppm. in an inert diluent or carrier,

such as water or acetone, preferably with a small amount of wettingagent, to the leaves of growing plants. Thus, when applied once togrowing soybeans when substantially fully leafed out, before flowering,an increase in ultimate crop yield is effected.

Analysis.Calculated for C H BrCl N 0- S: C, 38.3; H, 2.2; N, 6.9. Found:C, 38.5; H, 2.1; N, 6.9.

Other 2,6-dihalobenzaldehyde arylsulfonyl hydrazones which are preparedaccording to the method of Example 1 are given in the following table.

TABLE I Melting Example polnt number Compound C.)

2 2,6-dichlorobenzaldehyde benzenesullonyl- 125-130 hydrazone. 32,6-dichlorobenzaldehyde 4-methylbenzene- 189-193 sulfonylhydrazone. 42,6-dichlorobenzaldehyde 4-nitrohenzene- 193-197 sulfonylhydrazone.2,6-dichlorobenzaldehyde 4-methoxybenzene- 145. 5-

sulfonylhydrazone. 149. 5 6 2,6-dichl0robenzaldehyde 4-fluorobenzene-179-181 sulfonylhydrazone. 7 2,6-dichlorobenzaldehyde 2,4,5-trichloro-206-209 benzenesulfonylhydrazone. 8 2,6-diehlorobenzaldehyde3-nitrobenzene- 162-167 sult'onylhydrazone. 9 2,6-diehlorobenzaldehyde2-nitrobenzenesulfonylhydrazone. 10 2,6-dichlorobenzaldehyde3,4-dich1oro- 188. 5-19].

benzenesulfonylhydrazone. 11 2,6-dichlorobenzaldehyde 2,5-dichloro-203-208 benzenesulfonylhydrazone. 12 2,6-dichlorobenzaldehyde4-ehloro-2- nitrobenzeuesulfonylhydrazone. 2,6-dichlorobenzaldehydepentafluorobenzenesulfonylhydrazone. 14 2,6-dichlorobenzaldehyde4-chloro-3- 196-197 nitrobenzenesulfonylhydrazone. 152,6-dichlorobenzaldehyde 2,3,4-triehloro- 157-159benzenesulfonylhydrazone. 16 2,6-dichlorobenzaldehyde4-trifluoromethylbenzenesulfonylhydrazone;

Example 17 To a stirred solution of 7.7 gm. of methanesulfonylhydrazide(0.07 mole) in ml. of water a solution of 12 gm. of2,6-dichlorobenzaldehyde (0.069 mole) in ml. of ethanol in one batch. Asolid precipitates after which 300 ml. of ethanol are added. Thesolution is heated to reflux temperature and maintained at reflux forone hour. The mixture is filtered hot and allowed to cool slowly. Theprecipitate is collected by filtration and washed thoroughly with water.The white solid is 2,6-dichlorobenzaldehyde methanesulfonylhydrazone,M.P. -182" C.

Analysis.-Calculated for C H CI N O S: C, 36.0; H, 3.0; N, 10.5. Found:C, 36.0; H, 3.0; N, 10.6.

Other 2,6-dihalobenzaldehyde sulfonylhydrazones which are preparedaccording to the method of Example 17 are given in the following table.

the synthetic procedures described specifically in Examples 1 and 17 areuseful in the plant growth regulating method of the invention areexemplified, with intermediates which are used for their preparation, inthe following table.

TABLE III Intermediates Ex. Final products of No. Aldehyde Sulfonylhalide Formula I 25. 2,6 dilodbenz Methanesulfonyl2,6-dii0dobenzaldehyde aldehyde. chloride. methanesulfonylhydrazoue. 26.2-bromo-6chlorodo Z-bmmofichlorobenzbenzaldehyde. aldehydemethanesultonylhydrazone. 27. 2,6-dibromobenz- 4-bromobenzene-2,6-dibromobenzaldealdehyde. sultonyl chlohyde-a-bromobenzeneride.sulfonylhydrazone. 28. 2,(rdichlorobenz- 4-chlorosultonyl2,6-dichl0robenzaldealdehyde. acetanilide. hyde+acetamidophenylsultonylhydra- The synthesis of the novel haloalkylsulfonyl hydrazides isillustrated by the following examples.

Example 29 Hydrazine (13.9 g. of 97 percent, 0.42 mole) is added slowlydropwise, with cooling and stirring, to water (7.2 g., 0.40 mole). Thesolution is cooled to 10-15 C., and a solution of fiuoromethanesulfonylchloride (26.5 g., 0.20 mole) in tetrahydrofuran (300 ml.) cooled to5-10 C. is added dropwise with stirring, while maintaining thetemperature at -15 C. Stirring is continued for fifteen minutes aftercompletion of the addition, the mixture is filtered, and the filtrate iswashed twice with 70 ml. of saturated sodium chloride solution. TheWashed filtrate is dried over anhydrous magnesium sulfate, filtered, andpetroleum ether (300 ml.) is added. The mixture is cooled for 72 hours,and the product, an oily solid, is separated and dried in vacuo toremove solvent. The infrared spectrum of the product is consistent withthe assigned structure, monofluoromethanesulfonylhydrazide.

Example Using the method of Example 29, chloromethanesulfonyl chlorideis reacted with hydrazine to provide monochloromethanesulfonylhydrazide,m.p. 73-76 C. The infrared spectrum of the product is consistent withthe assigned structure.

What is claimed is:

1. Method of affecting the growth of plants. to bring about dwarfismcomprising growing plants with an effective amount of a compositioncontaining up to 2,000 parts per million of a compound of the formulawherein X is halogen and R is alkyl or haloalkyl of one to 16 carbonatoms, benzyl, phenyl or substituted phenyl radicals of the formulaReferences Cited UNITED STATES PATENTS 9/1970 Brepoles et a1. 7176 X7/1969 Nikles et al 71-103 X OTHER REFERENCES Munshi et al.: Chem.Abst., vol. 59 (1963), 12684d.

LEWIS GOTTS, Primary Examiner C. L. MILLS, Assistant Examiner US. 01.X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION hind June 18, 19'?Patent No. 3 8l7,7'40

It is certified that error appears in the above-identified plum and thatsaid Letters Patent are hereby corrected to ahoa'm below:

Column l, line ll, for "emulsifiers" read --emu1sifiable- Column 6,Table II, after the last printed line of the table 7 I add hydrazone-Column 7, in claim 1, second line, between "comprising" and "growing"insert -treating Signed and sealed this 29th day of October 1974.

(SEAL) Attest:

McCOY M. GIBSON JR. Attesting Officer C. MARSHALL DANN Conmissioner ofPatents Inventofls) Tomas L. Fridinger, Edward L. Mutsch & David R.Pauly OR PO-IOIO um V own-m4)! vacuum-0c pun-nu a maul-v mum: In!

